Brake assembly

ABSTRACT

A brake assembly includes a brake pad, a bracket supporting the brake pad and having a first portion, a second portion spaced apart from the first portion, and a linkage interconnecting the first and second portions. The linkage is configured to transfer tensile loads between the first and second portion, but is characterized by the absence of any bending modes. The absence of bending modes prevents excitation of the linkage, thereby reducing sound generated during application of the brake assembly.

TECHNICAL FIELD

This invention relates to vehicle brake assemblies.

BACKGROUND OF THE INVENTION

A disc brake assembly typically includes a rotor and a caliper. Therotor is connectable to a hub of a rotatable axle. The caliper includesa mutually opposed pair of brake pads supported by a bracket. Each ofthe brake pads overlies a respective rotor braking surface. Normally,the caliper keeps the brake pads separated from the braking surfaces ofthe rotor. The braking system is activated by moving the pads intocontact with the braking surfaces of the rotor; frictional interactionbetween the braking surfaces and the pads reduces or prevents rotationof the rotor relative to the caliper.

Brake squeal may be the result of modal excitations of the disc brakerotor (composed usually of cast iron) and the disc brake caliper by thefrictional interaction of the brake pads. Countermeasures to reducelow-frequency brake squeal include increasing the stiffness of thecaliper bracket by increasing the cross-sectional area of the tie-bars,and casting in or mechanically attaching a mass to the caliper bracket,wherein the mass acts as a vibration damper and/or changes the dynamicresponse of the caliper bracket.

SUMMARY

A brake assembly includes a brake pad, a bracket supporting the brakepad and having a first portion, a second portion spaced apart from thefirst portion, and a linkage interconnecting the first and secondportions. The linkage is configured to transfer tensile loads betweenthe first and second portion, but is characterized by the absence of anybending modes. The absence of bending modes prevents excitation of thelinkage, thereby reducing sound generated during application of thebrake assembly.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, perspective view of a brake assembly having acaliper assembly with a bracket;

FIG. 2 is a schematic, perspective view of the bracket of FIG. 1;

FIG. 3 is a schematic, top view of the bracket of FIG. 1;

FIG. 4 is a joint for use with the bracket of FIG. 1;

FIG. 5 is another joint for use with the bracket of FIG. 1; and

FIG. 6 is an alternative bracket configuration for use with the brakeassembly of FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a brake assembly 10 includes a caliper assembly 12and a rotor 14. The caliper assembly 12 includes first and second brakepads 16, 18, which are supported by a bracket 20. Referring to FIGS. 1and 2, the bracket 20 is generally U-shaped, and includes a firstportion 22, a second portion 26 spaced apart from the first portion 22,a first tie-bar linkage 30, and a second tie-bar linkage 34. Thelinkages 30, 34 interconnect the first and second portions 22, 26.

The rotor 14 in the embodiment depicted includes an inner portion 38that is generally ring-shaped. The inner portion 38 defines a centerhole 42 at which the rotor 14 is mountable to an axle (not shown), asunderstood by those skilled in the art. The inner diameter of the rotor14 at the hole 42 includes splines as shown for engagement withcomplementary splines on the axle. The inner portion 38 also has aplurality of threaded studs 46 protruding therefrom. As understood bythose skilled in the art, a wheel (not shown) is mountable to the rotor14 at the studs 46 such that the wheel and rotor 14 rotate as a unit.

The rotor 14 also includes an outer portion 50, which is generallyring-shaped and which concentrically surrounds the inner portion 38. Theouter portion 50 includes two opposing rotor cheeks 54, 55 havingventilation vanes 58 therebetween. Each rotor cheek 54, 55 defines arespective braking surface 62, 63.

Each of the brake pads 16, 18 overlies a respective rotor cheek brakingsurface 62, 63, i.e., the pads 16, 18 are positioned such that portionsof the rotor cheeks 54, 55 are therebetween. The pads 16, 18 areselectively movable between engaged and disengaged positions, asunderstood by those skilled in the art. When the pads 16, 18 are intheir disengaged positions, they do not contact the braking surfaces 62,63, and therefore do not cause any resistance to the rotation of therotor 14 and the wheel attached thereto. When the pads 16, 18 are intheir engaged positions, each of the pads 16, 18 contacts a respectivebraking surface 62, 63, thereby resisting rotation of the rotor 14 andthe wheel attached thereto. The pads 16, 18 may be moved to theirengaged positions through hydraulic actuation, electronic actuation,etc., as understood by those skilled in the art. The rate of braking isdependent upon the pressure of the brake pads 16, 18 against the brakingsurfaces 62, 63.

The linkages 30, 34 are configured to support tensile loads between thefirst and second portions 22, 26, but will not support a bending mode.More specifically, and with reference to FIGS. 2 and 3, linkage 30includes first, second, third, and fourth generally rigid links 66, 67,68, 69. The first link 66 is substantially rigidly connected to thefirst portion 22; the fourth link 69 is substantially rigidly connectedto the second portion 26.

The linkage 30 also includes one or more joints. More specifically, inthe embodiment depicted, the linkage 30 includes joints 70, 71, and 72.Joint 70 operatively connects link 67 to link 66; joint 71 operativelyconnects link 67 to link 68; and joint 72 operatively connects link 68to link 69.

Similarly, linkage 34 includes first, second, third, and fourthgenerally rigid links 74, 75, 76, 77. The first link 74 is substantiallyrigidly connected to the first portion 22; the fourth link 77 issubstantially rigidly connected to the second portion 26.

The linkage 34 also includes one or more joints. More specifically, inthe embodiment depicted, the linkage 34 includes joints 78, 79, and 80.Joint 78 operatively connects link 75 to link 74; joint 79 operativelyconnects link 75 to link 76; and joint 80 operatively connects link 76to link 77.

FIG. 4 schematically depicts a joint 82 interconnecting a first link 86and a second link 87. Joint 82 may be representative of joints 70, 71,72 and joints 78, 79, 80, and links 86, 87 may be representative oflinks 66, 67, 68, 69 and links 74, 75, 76, 77. Referring to FIG. 4,links 86 and 87 are formed from a single piece of material in which avoid 90 has been formed to separate the single piece of material intothe two links 86, 87. The void 90 in the embodiment depicted isconfigured such that link 86 defines a first hook portion 94 and link 87defines a second hook portion 95 that interlock with each other tosupport a tensile load between links 86 and 87, while preventing bendingmodes.

FIG. 5 schematically depicts another joint 98 interconnecting a firstlink 102 and a second link 103. Joint 98 may be representative of joints70, 71, 72 and joints 78, 79, 80, and links 102, 103 may berepresentative of links 66, 67, 68, 69 and links 74, 75, 76, 77. Joint98 is a hinge about which link 103 is rotatable with respect to link102. More specifically, in the embodiment depicted, link 102 defines ahole 106. Link 103 defines a hole 107. Holes 106 and 107 are alignedwith one another, and a hinge pin 110 extends therethrough. Hinge pin110 limits movement of link 103 with respect to 102 to rotation.Accordingly, when the links 102, 103 are at a 180 degree angle withrespect to one another, the joint 98 supports a tensile load, but willnot support a moment. Accordingly, the linkage formed by links 102, 103does not have any bending modes.

Referring to FIG. 6, wherein like reference numbers refer to likecomponents from FIGS. 1-5, an alternative bracket 120 for use in thecaliper assembly 12 of FIG. 1 is schematically depicted. Bracket 120includes first and second portions 22, 26 interconnected by linkages130, 134. Linkages 130, 134 are configured to transmit tensile loadsbetween the first and second portions 22, 26. Linkage 130 is a singlepiece of substantially rigid material in the embodiment depicted.Linkage 134 is a flexible member and, more particularly, a segment ofcable in the embodiment depicted. Accordingly, linkage 34 is unable tosupport a compressive load or a moment, and is thus characterized by theabsence of any bending modes.

Brake squeal is the result of excitation of either the brake rotor 14 orthe caliper bracket 20, 120. The caliper bracket modes that typicallygenerate brake squeal are the bending modes of the caliper linkages.Accordingly, the brackets 20, 120 may result in reduced brake squealbecause the linkages 30, 34, 134 do not have any bending modes.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

The invention claimed is:
 1. A brake assembly comprising: a brake pad; abracket supporting the brake pad and having a first portion, a secondportion spaced apart from the first portion, and a linkageinterconnecting the first and second portions; wherein the linkage isconfigured to transfer tensile loads between the first and secondportion; wherein the linkage is configured such that the linkage willnot support a bending mode; wherein the linkage includes a first rigidlink, a second rigid link, and a joint that interconnects the firstrigid link and the second rigid link; and wherein the first rigid linkdefines a first hook portion, and the second rigid link defines a secondhook portion that is interlocked with the first hook portion.
 2. Thebrake assembly of claim 1, further comprising a brake rotor; wherein thebrake pad is selectively movable between a disengaged position in whichthe brake pad does not contact the rotor, and an engaged position inwhich the brake pad contacts the rotor.
 3. The brake assembly of claim1, wherein the first and second rigid links are formed from a singlepiece of material in which a void has been formed to separate the singlepiece of material into the first and second links.